Transmission system



R. D. CONWAY TRANSMISSION 's'rng Filed March 29, 1920 all( Jan, 6%, 1925.

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wk@ Q IIIII I Patented Jan. 6, 1925.

UNiTi-:n STATES rATgENi" OFFICE.

ROY D. CONWAY, F ClHATHAM, NEW JERSEY, SSIGNOR T0 WESTERN ELECTRIC COM- PAINY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK. y

TRANSMISSION SYSTEM.

Appiicaiion mea March aa, 1920. serial No. aes-,soa

To all wwm it may cof/wem:

Be it known that I, ROY D. CONWAY, a citizen of the United States, residing at Chatham, in the county of Morris, State of New Jersey, have invented certain new and useful Improvements in Transmission Systems, of whichv the following is a full,

clear, concise, and exact description.

A This invention relates to a telephone transmission system. It relates more particularly to a telephone system in which a repeater isused in connection with a link or cord circuit for connecting line or trunk circuits to each other.

It has heretofore been customaryin using repeaters in a link circuit to associate with such repeaters a number of balancing sets for balancing the 'line vor trunk circuits to which the link circuit may be'conn'ected, in order to provide for rendering the repeater i paths connected to aline conjugate to each other. In such arrangements, it is necessary to have as many balancing circuits as there are line or trunk circuits of different characteristics, which may be associated with the link circuit. Manual means are sometimes used for associating the properbalancing` or articialline with the repeater and with the connected line or trunk circuit.

80 An object of this invention isto provide improved means for rendering the repeater paths connected to a line conjugate to each other.

A further object is to provide automatic means whereby the connected line or ltrunk circuit may be balanced when the comicotions `are set up. This is accomplished by i selecting means which automatically adjust in some cases the ei'ective values of an 40; electrical network which is adapted to be associated with any desired line and which iny other. cases automatically-'adjust the effective turns of transformer windings in circuit with the network and .the line in' accordanceA with -the characteristics of the .line to be balanced. -A balancing network may be.' permanently associated with the outputtransformer so that the line of maximum impedance may be balanced merely by adjustment of the effective number of `sertsthe plug P at the calling. end of lhe'r turns of transformer windings in circuit with the network and the line, and automatic selecting means may also Ibe associated 4with the repeater which 'will operate to vary the characteristics of the artificial or balancing network in accordance with the characteristics of other lline or trunk circuits with which connection may be set up. v The invention will be understood by reference to the accompanying drawing which shows a cord circuit having two one-Way amplifiers of the vacuum bulb type .connected therein, and having associated therewith automatic `se1ector means for balancing' the line circuits.- The two .way transmission'of signals is made possible by the well-known wheatstone bridge balancing method. The jacks J and, J- of two line circuits which are provided with the usual signalling means, etc. l(not shown) are kindicated on the drawing. When the operator, upon receiving the* proper signal in- ,sertsplugPy at thel answering end of her cord, finto the jack J of a calling subscriber, .the relay 1 is energized by a circuit from ground, through battery, resistance R, relay 1, sleeve-contacts 'o plug Pfand. jack J, relaiy 2,-to ground. .Upon receiving the number `of the desired party she then incord circuit into the jack J of thecalled subscriber, thereby establishing a 'circuit from ground thrughfrbattery, resistancev R', relayfrl, sleeve contacts of plug P and jack J', relay 2', to ground. The contacts of relay '1 and 1" are thereb closedfbut relays 2 and 2v being marginal, are not operated. l The operator-then presses her ke K in orderr to associate the roper ba ancing lines -with vthe repeater Rar balancing the connected-lines'. Closing of key K estabv lishes a circuit from v.ground through battery, wire 3, contact 4 of'relay 1, wire -5, key

K, wirev 6, cont-act of relay 1', wire 7 relay 95 C, to ground. This operates relay C, there by closing its .upper and lower contacts.v

in the'drawing. Two other relays-C, and C2 corresponding to other cordI circuits are shown, and it` is obvious from an inspection of the connections of, the same that when any one of the relays C, C C2, etc., is energized. lto cause thel automatic selecting means to operate to select the balancing networks for two connecting linesnone of the other cord circuit selecting means can operate at 'the same time.`

' The closing of the upper and lower contacts of relay C, by means of the circuit above traced, establishes a circuit|from battery through a lower contact of rela C,

wires .8 and 9, upper contact of relay (j, re#

. and 14, left contact of'relay 25, wire 15, and relay 16 to ground, thusenergizing relayl and closing its contacts. The current throughwire 14 also divides atthe point 14 Vandpasses through relaygl7, wire 18, resistance R4, through back contacts of relay 20, 20, or, 202, to ground, thus energizing relay .30 17 and closing its contact.

The lclosing of the contacts of relay 16 establishes a circuit from battery through the upper movable contacts of relay 16 and then through thethree parallel circuits as follows: Marginal relay 21, resistance Rm,

motor magnet 22, extreme lower contact of relay 16 to ground marginal relay 21 resist- ,ance R82, motor magnet 22 intermediate lower contact of relay 16 to ground; and

.marginal relay 212, resistance R23, motor magnet 222, lower Contact of relay 16 to ground. This starts the motor magnets to operating, thereby revolving the wiper arms of the rotary selector switches S, S and S2. One of the contacts of row of each one of the rotary switches S, S1 and S2 is connected by means of the wires 10, 11 and 12, to the contacts of relay 2 so that these wires will all be grounded when relay 2 is energized. The motor` magnets 22, 221 and 222 step up the wipers, until they reach the points grounded through the contacts of relay 2, when the motor magnets are short-circuited and the wipers consequently rest on these grounded points. The increased current through the marginal relay 21 due to the wire 23 beingl grounded through switch S and wire 10 will cause the` marginal relay v21 to be energized, thereby closing its contact. A similar vop- 0 eration occurs with respect to the marginal relays 21 and 212, thereby closing their contacts.

`Closing the contact of relay 21 establishes` aY circuit which may be traced frombattery through the lower contact of relay C, wire 8,

mamas front contact of relay 17, resistance R, wire 19, relay 20, and front contact of relay 21 to ground thereby energizing relay 20 and locking the 'circuit to ound through its right-hand contact. T e energization of the relay 20 opens the circuit from the wire 18 through the left-hand contact of relay 20. In a similar way, the short-circuiting of the motor relays 22,L and 222 cause the operation of the marginal relays 21, and 212 thereby locking the relays 20, and 202 to ground and l 202 locked and causing the operation of the( relay 24.

The energization of relay 24 by means of its movable contact, establishes a circuit from battery through lower contact of relay C, wire 8, front contact of relay 24, slowacting relay 25, to ground, thus closing all of the contacts of relay 25. Energization of relay 24 also opens at its back contact the circuit previously traced from battery through .wire 9, lower contact of relay C, relay 1 and relay 2 thereby deenergizing relay 2 and caissing its contacts to open and remove ground fromwires 10, 11 and .12.. Closing of the right-hand contact of relay 25 shifts battery on relay C through a circuit which may be traced from ground through battery, right-hand Vcontact of relay 25, contact 4 of relay 1. contact of rela 1, key K, wires 6 and 7 relay C to groun The energization of relay 25 also breaks the circuit through wire 15 at the back outer left-hand contact of relay 25 thereby deenergizing relay 16 whose contacts open and remove battery vfrom the marginal relays 21, 21, and 212 and motor magnets 22, 22 and 222 thereby permitting the wiper arms of the switches S, S, and S2 to remain in the positions to which they have been moved. The tip and ring 'contacts of the plug T .are connected to the transformer T and the line winding of the transformer T 1s connected by means of the wires 30, 30 through wires 32 and 32 to the wiper arms of the lswitch S which wipe over the associated two rows of contacts, lthereby making connections with the proper capacity C1'. The wires 30 and 30, are also connected through the wires 31 and 31, to the wipers of switch S2 which wipe over the associated rows of contacts to connect the proper `resistance Rl.

aaa

A suitable number of points on'the line 18@ i winding of the transformer Tare connected output side of the vacuum bulb B,

lments R, and C12 to the rows 46, 47 of contacts of the switch S, so that the wipers of this switch S may connect the same to the pair of wires 29, 29 which lead to the primary winding of the transformer t. i

The other winding of the transformer T is .connected through -wires 34, 341, to the andthe secondary winding of the transformer t leads to the input side of the vacuum bulb A.

All of the corresponding contacts in the row 45 of the switches S of all the cord circuits will be connected in parallel to the same wire 10 sothat the wipers will be stopped at the proper point irrespective-of the cord circuit with which the connection is set up, There will be as many contacts in the row 45 of contacts. of switch S as there are line circuits of .diHerent characteristics which itis desired to balance. The balancing network consisting of the elewhich correspond to the first position of switchesS1 and S2 will be such that the line circuit ofminimum impedance may be balanced without shifting the wiper arms from their initial positions.

When vline circuits of other characteristics are connected, the selector switch S1 and S2 may connectIl other balancer elements to the wires 30, 30' so as to obtain proper balancing. Or the proper balancing maybe obtained for line circuits of other characteristics by allowing selector `switches S1 and S2 to maintain the same amountof capacity and resistance in the artificial line, the connection in the effective impedance of the artifcial'line being made by stepping selector S around until the proportions included' in the real line circuit and the artificial line circuit bear such a relation to each other that the desired balance'4 is obtained. For example if S1 and S, give the artificial line v too high an impedance to balance the new 45 line selector switch S should operate to include more turns of the transformer windings in the real linecircuitand less turns in the artificial line branch.

It is obvious that the connection of the balancmg elements to wires 30 and 301 may be made in other suitable-ways besides the parallel relationdescribed above. The connections of the outer contactsof the rotary switches S, S1 and S2 are so made that the energization of the marginal relay 2 of any line circuit Will cause the-.wipers of the rotary switches S, S1 and S2 to'stop. at such 4points that the proper adjustment is made the input of the trans.

between the leads of former and the taps of the output transformer, and the appropriate balancing networks are also associated with the transformer T, in accordance with the characterlstics of the particular line to which connection 1s made.

In order to trace the circuits by means of n which the adjustment and selection of balancing networks for the called line are made, it will be noticed that the closin of the left-hand contacts of relay' 25, a ove described, establishes a circuit from battery.

' `lower contact of relay C, wire 8,'1eft-hand contact of relay 25, wire 27 back contact of relay 24', relay 1',sleeve contacts of plug P', and jack J', marginal relay 2 to ground. The increasedcurrent through relay 2', thereby causes .it to operate and close its contacts so that the wires 10', 11' and 12'l are grounded for a sim lar purpose for which the .wires 10, 1 1 dnd 12 had been grounded. l

vThe energization of the relay 25 also 'establishes a circuit which may be traced fromv battery through'lower contact ofrelay C,wires 8 and 14, left-hand contact of relay l25, wire 26, backV contact of relay 25',` and wire 15' from which 1t goes to a relay for the similar circuit at the answering end of the cord circuit. Thelcalling end of the cord circuit is provided with exactly the same equipment as is shown for the answering end and the operation is exactly the same. When the rotary switches have reached` the contacts whichare grounded through the wires 10', 1l', and 12', relay 17' becomes deenergized inthes'ame way as already explained for relay 17. This of relay 17', relay 24', resistance R'1, wire 19' to ground, in a manner similar to that already traced for opera-ting'relay 24 closes a circuit which may be traced from battery to the. lower contact of relay C, -wires 8 and 14, left-hand and wire 18 in exactly the closes.- contact from wire 26 through back conta'ct the answering end of the lcord circuit. The energization of slow contact of relay 25, wire 27 front contact of I relay 24', through relay 25 to ground. The energization of relay 24 also opens' at its back contact the circuit previously tracedthrough wire27, relay 1 and relay 2', thereby deenergizing relay 2" and causing its contacts to open and relnove ground- The energi-A from the wires 10', 11' and 12'. zation of the relay 25' opens the circuit through the wire 15', thereby deenergizing the relay. of thecalling end of Athe cord c ircu'itcorresponding to the relay 16 of the i answering end of the cord circuit, thus permitting the corresponding rotary switches.

o maintain lproper balancing of the called ine.

The energization of the rela 25" also shifts battery on relay 25 throug i a circuit which may be traced from ground, through battery, right-hand contact of relay -25, wire 4,' contacts of relay 1, key K, wire 6, contact of relay 1 left contact of relay 25', left-hand contact of relay 24, through relay 25 to ground.A Closing the left-hand contact of relay 25 opens the circuit through wire 7 and relay C to ground, thus causing the deenergization of relay C, so that the selector apparatus associated with another cord-dircuit may operate.

'llie tip and ring contacts of plug P are connected to the transformer T and connections are made to the repeaterk from the transformer T and tov thevselector switches for the calling end ofthe cord circuit in exactly the same way as has been explained,y

for the answering end of the cord circuit.

By tracing the circuits, it is seen that when an operator inserts the plugs P and ll into the jacks J and J, and presses her key, the rotary switches S, S1 and S2 operate first, to associate proper networks with the calling line, after which corresponding switches operate to associate proper networks with the called line, and when the connections have been set up and the lines balanced, the relay C) becomes deenergized, thereby per- Amitting other cord circuits to be used for setting up connections between two line circuits, and balancing the same. After thewipers of the selector switches have reached their proper contacts, the relays 17 and 17 are Y, also deenergized as above explained.

When both plugs P and P a'e withdrawn from the jacks, the relays 1 a d 1 become deenergized and the apparatus is .restored to normal.` The wipers of the -rotary vswitches remain in the positions to which -they have been moved, so that when other connections are set up, they will begin to be stepped up in order to reach the proper t points for balancing -the newly, 'connected lines if such lines differ in characteristics from the ones last connected. If the plug at one end only of the cord circuit is withdrawn from a line jack, its corresponding 'relayvl or 1 is deenergized and when this plug is insertedl into`a line jack of a line having a different characteristic, the relay 1 or l is again energized and the elector switches vbegin their travel to asso iate a proper balancing network with the newly connectedline. A

j What is claimed is:

1. In a signaling system, a plurality of lines terminating at a central station, a link ,circui,t, a repeater unit in said link circuit having input terminals and output terminals, a transformer in said link circuit,

connections from one set of said terminals two one-way amp'liiersin said link circuit,

an input transformer and an output transformer connected on each side of said repeater unit, and means for automatically connecting the leads from the primary windings of said input transformers to different parts of the line windings of said output transformers in accoidance with the characteristics of the line circuits to Which said link` circuit is connected.

3. In a telephone system, a plurality of line circuits terminating at a central station, a linkl circuit, a repeater unit in said link circuit, an input transformer and an output transformer connected to said repeater unit, and a selector switch for automatically connecting the leads from the primary winding of said input transformer to different parts of the linewinding `of said output transformer in accordance with the characteristics of the line circuit to which said link circuit is connected. i

4. In a telephone system, a plurality of line circuits terminating at a central station, a link circuit, a repeater unit consisting of two plie-way amplifiers in said link circuit, an input transformer and an output transformer connected on each side of said repeater unit, ,and selector switchesfor automatically connecting the leads from the primary windings of said input transformers to different parts of the line windings of said output transformers in accordance with the characteristics of the line circuits to which said link circuit is connected, and an operators key for cntrolling said selector switches. f

5. In a telephone system, a plurality of line cir-cuits terminating at a central station, a link circuit, a repeat-er unit in said link circuit, an input transformer and an output transformer connected to said repeater unit,

and means for automatically connecting the output transformer connected to lsaid re lil@ i liti peater unit, and means for automatically adjusting the connections from the primary winding of said input transformer to different parts of the line winding of said output transformer in accordance Vwith the characteristics of the line circuit .to which Y said linkcircuit is connected, and means a selector switch for automatically connecting' the leads from the primary winding of said input transformer to different parts of the line winding of' said output transformer in accordance with the characteristics of the line circuit to which said link circuit is connected, andl selector switches for associatingresistance and capacity with said connected line circuit. a

8. In a tele-phone system, a plurality of line'circuits terminating at a central `station, a link circuit, an Aoperators key associated with said link circuit, a repeater unit consisting of two one-way amplifiers in said link circuit, an input transformer and. an output transformer connected on each side of said repeater unit, and means operable when said'key is pressed, for automatically connecting the leads from the pris mary windings of said input transformers to different parts of the line windings of said output transformers in accordance with the characteristics of the line circuits to which said link circuit is connected. y

9. In an electric system,.a plurality of line circuits, a link circuit adapted to be connected between two of said line circuits, said link circuit comprising an impedance device and an artificial line, said impedance device being in circuit with said artificial line and one of said connected lines, an e'lectricalconnectlon to an intermediate point of said impedance and electro-responsive means for -varying the point on said impedance to which said electrical connection is made in accordance with. thev characteristics of the line circuit to which said link circuit is connected.

10. .In an electric system, a plurality of lme circuits, a repeater circuit adapted to beconnected between two of said line circults, said repeater circuit comprising a transformer and an artificial line, said transformer having a winding in circuit with said artificial line and one of said connected lines, an electrical connection ,to an intermediate point of said winding, and means acting in response to the connection of one o f saidv line circuits to said repeater circuit for con;L necting said electrical connection to different the line circuits to which said repeater cir-` parts of said winding in accordance with the characteristics of the line circuit to which said repeater circuit isconnected.

11. In an electric system, a plurality of line circuits, la repeater circuitadapted to be connected between two of said lin'e circuits, said repeater c1rcu1t`,comprislnga transformer and an artificial line, said transformer having a winding in circuit with said artificial line and one of said connected lines, said artificial linehaving an impedance differing from'the value of the im-l pedance of one of said connected lines, an electrical connection to an intermediate point of said winding, and means acting in response to the connection of said link'circuit to one of said line circuits for connecting said electrical connection to different parts of said winding in accordance with .the characteristics of one of the line cirf 35 huits to which said repeater circuit is connected.

12. In an electric system, avplurality of line circuits, a repeater circuit adapted to be connected between two of said line circuits, said 4repeater circuit comprising a transformer and an artificial line, said transformer having a winding' in circuit with said artificial line and one of said connected lines, said artificial line having an' im- 95 pedance differing from the impedance of one of said connected lines, said winding having a plurality ofv taps an electric circuit adapted to be connected to one of said taps, changing the tap to which said last mentioned electric circuit is connected in accordance with the characteristic of one of cuit is connected. t

13. In an electric system, a plurality of line circuits, a linkv circuit adapted to be connected between two of said'line circuits, a Wheatstone bridge type off'network in said system, one arm Bf which comprises oneof said line circuits, a/second arm of which comprises said artificial line, a third arm vof which comprisesJ al circuit for incoming currents for said/link circuit, a fourth arnr'y of which comprises a circuit for out- 115 going currents for' said linkcircuit, anv impedance device, fa portion of Which 1s 1n said first arm; another portion of which is i-n,\ said second arm, and electro-responsive means Afor/varying the relative proportions of said impedance included in. said first two -arms in accordance with the characteristics ofthe line circuit in said first arm.

14. Inv combinatiom'a signallng Aline, an

artificial line for balancing said signaling line,fand means for determining a characteristic of said artificial line, said means comprising a plurality of stationary contacts, ai movable member cooperating with said contacts and electroresponsive means depending 13 and electro-responsive means for 100 Qa assi upon a characteristic of said signaling line for varying the position-of ysaid'movablev member.

15. In combination, a signaling line, anartificial line comprising impedance elements for balancing the said signaling line, and means for varyingthe eective'value of said impedance element, said means comprising a; plurality of stationary contacts each connected to a point on said impedance, a movable member cooperating withsaid contacts, and electroresponsive means depending upon a characteristic of said signaling line and operative only after said signaling line is connected to said artificial line for vvarying the position of said movable member.

16. In combination, two line sections, a two-way repeater circuit between said line sections, anartificial line for balancing each of ,said linevsections, a rotary switch for varying the effective value of an element of one of said artificial lines, and an electro-- responsive means for operating said rotary switch to a position determined by a characteristic of its associated line section. f f 17. In an electric system including a plurality-of lines, a link circuit, said link circuit having a transformer winding in series therein and said link circuit being adapted toy be connected between two of said lines at A a time withone end of said winding connected to one of said two lines and the other end of said winding connected to the other circuit and said circuit means and comprisof said two lines, said system also including an adjustable connection to said winding,- and electroresponsive means for moving said connection to a position on said winding which ris intermediate to pointsof connection of said winding ,to 'said two lines and a characteristic of connection to a second 'position determined by a characteristic of another of said lines vsubsequently connected to said link circuit.'

18. lIn an electrictransmission network, a circuit, a multi-winding transformer, circuit means, means connected between said ing a winding of said transforrner, said circuit means presenting a variab e impedance.

to said connected means, a circuit adjustably connbcted to said lwinding of said transformer, av circuit in conjugate relation to said adjustably connected circuit, and means operating in response to variation of saidvariable impedance lfor adjusting said atljustable connection to such a positionon said winding that said conjugate relation is maintained.

19. In combination, a plurality of signaling lines, each having a different characteristic impedance, a multi-winding transformer, a line impedance balaicing 'network, means including a winding of said transformer for connecting said network to each oftsaid lines, one line at a time, with said winding of said transformer in series with said connected line and said network, repeater terminals connected to a second winding of said transformer, other repeater terminals, and means for connecting said otherrepeater terminals to a common terminal of said network and said connected line, and to any one of a plurality of intermediate points of said .first winding, said points of connection to said firstl winding being so located on said first winding that said first winding may be unequally distribmeans including lpart of the windings of said transformer for connecting said network to each of said lines, one line at a time, repeater terminals connected to another part of the windings. of. said transformer, other. repeater terminals, and means whereby said other terminals' may be connected to such points on said first part of said transformer windings that when one of said lines is connected to said network by said first mentioned means, said other repeater terminals are4 prevented from receiving electromotive forces impressed on said line through said second part of said transformer windings, and whereby said other terminals may be connected to such points on said first part of said transformer windings that when another of said lines is connected to said network by said .first mentioned means, said other repeater terminals are prevented from receiving electromotive for es impressed on said line through said second part of said transformer windings. v y

In vwitness whereof, I hereunto subscribe my naine this 25th day of March A. D., 1920.

Roi n. coNwAif. 

